Go down into the section called: “Select how your app integrates with Facebook”

Find setup for Page Tab and check if you have set correct width of used app layout (mine was 520px)

Save changes, if anything changed

Than on the left choose Settings -> Advanced

In the section “Canvas Settings” should be following setup for canvas height: fluid

If above described setup is ok, than we have to fix it in our application. It is simple, with two code snippets. Just add following before </body> tag (If You are not using Facebook init script already):